engine surge problem

N

njboat

New Member
Jun 6, 2012
19
indiana
Boat Info
1976 sea ray seven 195
Engines
351 w
Hey guys, i hope everyone is enjoying the boating life this year. The reason for my post is that my mercruiser 233 ford 351 is surging. It seems that after first launching the boat and about the first hour or so everything works picture perfect. Then at about half throttle my engine surges and does not want to make power. Very hard to get on plane. My thought is the fuel pump but does not make sense to me that it runs great for so long before i have issues. Any advise would be greatly appreciated. Thanks and enjoy the water :grin:
 
I have same problem with same engine.I can idle all day soon as hit gas it surges and pops wont plane.
ran fine last year.My engine does it right away.I have at shop now he is thinkin timing issue possible distributor not advancing
Being that your happens after a while i would think coil.Ill let you know what he finds hope it help your issue also
 
Thank you. I also thought that could be a possibility but was not sure. I will surely try the coil. Would love to hear if that fixed your problem as well. Thanks for the tip as soon as i get a chance to check it out i will let you know
 
Just remembered we had a van that would run fine until it heated up. Turned out to be a hairline crack in the distributor that would expand with heat and cause erratic running issues or no start at all.
 
Thank you. This is another great idea i will try before i head out on the water next. Just changed coil last night hope to get the boat out after work one night this week if not this weekend. Thanks again for the tip.
 
1973240srv i was curious about the prop pich and speed that your boat runs. Not 100% on the pitch of mine but trying to raise my top end speed. My boat is 19.5' long and personally believe it should top out better than 39mph.not complaining about hole shot at all but just think that a rebuilt 351 would be a little quicker. Any thoughts?
 
njboat said:
1973240srv i was curious about the prop pich and speed that your boat runs. Not 100% on the pitch of mine but trying to raise my top end speed. My boat is 19.5' long and personally believe it should top out better than 39mph.not complaining about hole shot at all but just think that a rebuilt 351 would be a little quicker. Any thoughts?
Click to expand...
prop pitch would be totally different on a 195 and a 240.
get her running right first
 
O.P., I would look to an ignition component breaking down. My buddy's 21' Spectra w/454 would run great for about an hour and then would die at anything other than idle or just above. Any load would kill it. He decided to swap out his Mallory electronic distributor and go back to tried and true points. He reports that his boat now runs like a top. I presume his pick-up in the distributor was failing when hot. I don't know what ignition system you have, but it's worth a good look.

To the guy with the boat that runs bad after storage, I'd look to the carb if that's what you have. Carbs like to crust up when not used. This can restrict or plug internal passages causing bad driveability problems. Typically a thorough cleaning and a carb kit will whip it back in shape.
 
I had similar issues at different times on my 454's. One turned out to be a bad sending module in the distributor and the other one was a very small air leak on the fuel filter seal (suction side).

So one was loosing spark and the other was sucking air rather than fuel.
 
I had this problem after a hard drive strike. Engine would rev, but little power. It would come and go for a few days, and i finally pulled the boat and had it looked at as an insurance claim.

Drive upper seals blown, gear lube mixed with water. Yoke needed replacing but that was from normal wear. I replaced both Alpha 1's with SEI drives and have had no issues at all.

If its possible, pull the boat and check the gear lube for quantity and water.
 
Thanks for both of these tips. I changed the coil and also have checked for any possible air leaks i hope to take her out after work today if the weather cooperates. As far as the drive goes it seems to have power and works great but will deffinately drain the oil and check it out thanks. The problem seems to be in the motor.
 
No need to totally drain, just open the vent and open the bottom and attach the filler, you should notice shavings or milky coloured oil if water has invaded. If not, measure how much oil you can get in. It should almost immediately start coming out the top, and be the same colour as what came out the bottom.
 
Good point on the sucking air. I had a different problem with an old truck one time, it was a fuel restriction. It would idle all day long, but once you started driving, it would die at about 1/2 mile. You could start it right up and take right off again, but would die after 1/2 mile again. It ended up being the fuel line coming from the tank was nearly plugged with deposits. The pump couldn't draw enough fuel to keep the carb full under load, just enough to keep it going at idle or slightly above.
Travis..
 
Photobucket, or become a silver member on the site and you can upload picts here for display.
 
To follow up with the engine surge problem i just wanted to let everyone know that it ended up being the coil. Finally got the boat back out yestrrday and she ran like she was brand new again. Thanks for all the helpfull hints.
 
ended up being water in tank enthenal causing major issues here in buffalo ny
drained almost gallon of water.DO NOT USE DRY GAS MAKES PROBLEM WORSE use stabil ethl treatment or K100 marine treatment
seems to running better
 
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